Historically, it has been difficult to inflict catastrophic damage on thin-skinned targets using a long-range gun. The problem is even more pronounced with thin-skinned, fuel filled targets, such as fuel tanks, fuel containers, or fuel storage facilities. Conventional projectiles, such as MK211, M8, or M20 armor piercing incendiary (“API”) projectiles, are designed to penetrate armor plating and to provide an incendiary flash. To provide the penetrating effects, the MK211, M8, and M20 API projectiles typically include a fill material that is an incendiary composition. For instance, in the MK211, the fill material includes zirconium sandwiched between Composition B. While these projectiles penetrate thin-skinned targets, the fill material does not initiate when the projectiles come into contact with the target surface. Rather, the projectiles pass through the thin-skinned target and do not ignite fuel that is contained within it. As such, the MK211, M8, and M20 API projectiles have limited effectiveness against thin-skinned targets.
A fill material for use in an armor-piercing projectile is disclosed in U.S. Pat. No. 4,237,787 to Wacula et al. The fill material is an incendiary composition that includes aluminum or magnesium, a nitrate or peroxide of potassium, strontium, or barium, and a binder, such as a chlorinated binder. U.S. Pat. No. 4,112,846 to Gilbert et al. discloses an incendiary material having a first metal, which interacts with a second metal to form an intermetallic compound. The first metal is zirconium, titanium, thorium, hafnium, uranium, or mixtures thereof and is present from 70-98.5% by weight. The second metal is tin, lead, or mixtures thereof and is present from 1.5-30% by weight. Incendiary compositions having various properties have also been disclosed. In U.S. Pat. No. 6,485,586 to Gill et al., a low burning rate, high temperature incendiary composition is disclosed. The incendiary composition includes titanium, boron, polytetrafluoroethylene (“PTFE” or TEFLON®), and paraffin wax.
Incendiary materials have also been used as liners in projectiles, such as in warheads. In U.S. Pat. No. 4,381,692 to Weintraub, a quasi alloy zirconium (“QAZ®”) material is disclosed for use in munitions. QAZ® includes a long chain epoxy and a powdered metal mixture of zirconium, aluminum, hafnium, magnesium, antimony, tin, and iron. Reactive or energetic materials have also been disclosed for use as liners in projectiles. A known reactive material includes a composition of aluminum and PTFE, as disclosed in U.S. Pat. No. 6,547,993 to Joshi. In U.S. Pat. No. 5,886,293 to Nauflett et al., a process of producing energetic materials for use in military pyrotechnics is disclosed. The energetic material includes a magnesium fluoropolymer, specifically magnesium/TEFLON®/VITON® (“MTV”).
In order to defeat thin-skinned targets and particularly those housing flammable materials, such as fuels, it would be desirable to produce projectiles that initiate on contact with the thin-skinned target. Therefore, it would be desirable to formulate fill materials that provide a higher energy output than those currently used, such as in the MK211.